Recording video in the 1950s

[Mike Watterson]

Allegedly U-matic is why 44.1 KHz was chosen rather than any other frequency from 40 KHz to 50 kHz for digital audio sampling prior to 48/96/192.

I always though that 44.1kHz audio sampling was devised for CD. The lowest rate you could get away with for full quality audio. The claim for it being based on Umatic is repeated here, but without evidence: https://en.wikipedia.org/wiki/U-matic

There were digital audio recorders based on both Umatic (PCM16xx) and Betamax (PCMF1).
PS: I've looked in "The art of digital audio" by Watkinson. He is usually a reliable source. He makes a fairly good case for 44.1kHz being due to the limitations of the PCM1600. Without finding original sources I'm not sure his argument fully stands up. 48kHz is a good fit for video, as has been demonstrated by its near-universal use in a broadcast environment.

I'd heard the Betamax claim years ago. Obviously the Nyquist frequency has to be not just above highest desired audio frequency but take into account having flat enough anti-aliasing pre-filter to that frequency and then the rejection of the filter low enough at Nyquist frequency. So why not 42kHz, or 44, or 45 or 48 kHz? The 48 kHz would probably work with same ADCs etc and reduce demands of analogue filter design. People tend to also pick round numbers and also as high as possible for sampling (using same cost of HW) to reduce filter cost.

In 1973, his team developed a digital PCM adaptor that made audio recordings using a Betamax video recorder.

https://en.wikipedia.org/wiki/Compact_Di...ital_Audio

Obviously not a reliable source, because the retail Betamax was released in 1975. The Umatic was sold from 1971 and working prototypes a year or more earlier. Philips CD development started about 1974. Sony joined in 1979. According to Wikipedia "The Compact Disc Story" explains the reason for
44.1 kHz sampling. https://www.aes.org/e-lib/browse.cfm?elib=12144

To me the idea that a U-matic was used for storing digital audio rather than a Betamax (originally) fits the time line better.

The NTSC line rate is 15.75 kHz and PAL is 15.625 kHz.
However 44.1 kHz is 1470 x 30 Hz or 1764 x 25 Hz. But 48 kHz gives 1600 or 1920.

Maybe the paper gives a good explination for the 44.1 kHz (as opposed to any whole number from 40 kHz to 50 kHz).